High molecular weight alkenyl-n-omega amino hexylsuccinimide



United States Patent 3,194,813 HIGH MQLECULAR WEEGHT ALKENYL-N- OfiiEGAAMINO HEXYLSUCClNIh HDE William M. Le Suer, Cleveland, and George R.Norman,

Lyndhurst, Qhio, assignors to The Luhrizol Corporation, vWichliife,Ohio, a corporation of Ohio,

No Drawing. Filed Oct. 18, N62, Ser. No. 231,554

2 Claims. (Cl. 260-6265) This invention relates to oil-solublenitrogen-containing compositions and to the process of preparing thesame. The compositions of this invention are useful as dispersing agentsin lubricants, especially lubricants intended for use in the crankcaseof internal combustion engines, gears, and power transmitting units.

One of the principal problems associated with presentday crankcaselubricants is that posed by the inevitable presence in the lubricant offoreign particles such as dirt, soot, water and decomposition productsresulting from breakdown of the lubricating oil. Even if there were noneof this latter contaminant present the very nature of the design of themodern internal combustion engine is such that a significant amount offoreign matter will accumulate in the crankcase. Perhaps the mostimportant of these contaminants is water because it seems to beresponsible for the deposition of a mayonnaise-like sludge. It appearsthat if there were no water present the solid components of themayonnaise-like sludge would circu late with the oil and be removed bythe oil filter. It will be readily appreciated that the deposition ofthe sludge presents a serious problem with respect to the efficientoperation of the engine and that it is desirable to prevent suchdeposition of sludge-like material.

The presence of water and the precursors of sludge in a lubricating oilis dependent largely upon the operating temperature of the oil. If theoil is operated at a high temperature the waterr, of couse, will beeliminated by evaporation about as fast as it accumulates. In theabsence of water as stated above the other foreign particles will beremoved by the filter. At low oil temperatures, on the other hand, waterwill accumulate and so consequently will sludge. It is apparent that theenvironment in which a crankcase lubricant is maintained will determineto a large extent the ultimate performance of that lubricant.

High operating temperatures are characteristic of a Inbricant in anengine that is run at relatively constant high speed. Thus, in an enginethat is run at 60 miles per hour for a long period of time it is veryunlikely that there will be any accumulation of water and it issimilarly un likely that there will be any formation and deposition ofsludge, but in ordinary stop-and-go driving, the crankcase lubricantwill be alternately hot and cold, an ideal enviornment for theaccumulation of water. In such cases the formation of sludge is aserious problem. This problem has been withv the automotive industry formany years and its solution has been approached by the use of knowndetergents such as metal phenates and sulfonates but without notablesuccess. Although such known detergents are very effective in solvingthe detergency problems associated with motor oils at high temperaturesthey have not been particularly effective in solving the problemsassociated with low temperature operation, or to put it better, thoseproblems which are associated with crankcase lubricants in engines whichare operated at alternating high and low temperatures.

It is accordingly a principal object of this invention to provide novelcompositions of matter.

It is also an object of this invention to provide compositions which areadapted for use as additives in hydrocarbon oils.

It is also an object of this invention to provide compo- "ice sitionswhich are effective as detergents, in lubricating compositions.

It is another object of this invention to provide a novel process forthe preparation of products which are effective asdispersants inlubricant compositions.

It is another object of this invention to provide novel compositionswhich are effective dispersants in lubricant compositions intended. foruse in engines operated at alternating high andlow temperatures. 0

It is another object of this invention to provide improved hydrocarbonoil compositions.

It is another object of this invention to provide, improved lubricatingcompositions.

These and other objects are achieved in accordance with this inventionby providing a succinimide having the structural formula O RCHN-(0Hz-)sNHz bHz-C ll wherein R is a polyisobutene radical, having fromabout 50 to about 200 carbon atoms.

A critical aspect of this invention is that the polyisobutene radical.contains at least about 50 carbon atoms. The criticality is predicatedupon the discovery that a. similar succiniinide having a smaller Rradical in its mo lecular structure is not useful for the purposes ofthis. invention.

The sources of the R radical include polyisobutenes having molecularweights within the range from about 7,00 to about 3000. Such polymersare well known in the art. They can be obtainedfor instance, bycontacting isobutene, preferably in a solvent such as hexane, butane, ornaphtha, with, a Friedel-Crafts catalyst such as alumi num chloride,boron trifiuoride, zinc chloride, or titanium tetrachloride at atemperature between about 50 C. and 25 C.

The polyisobutene-substituted succinimide of this invention is obtainedby the reaction of approximately equimolar mixtures of an appropriatepolyisobutene-substituted succnic anhydride or acid with hexamethylenediamine. The reaction between an anhydride and the diamine isillustrated by the following equation: i

The reaction should be carried out at a temperature which issufiiciently high to cause the removal of water from'the, reactionmixture. Ordinarily the temperature isbetween about C. and 250 C.,preferably between aboutmolecular weight; The reaction involves merelyheating the two reactants at a temperature about 100200 C. The productfrom such a reaction is an alkenyl succinic anhydride, the alkenyl groupmay be hydrogenated to an alkyl group. The anhydride may be hydrolyzedby treatment with water or steam to the corresponding acid.

The following example illustrates the preparation of the succinic imidesof this invention (parts are by weight):

Example 1 A polyisobutene-substituted succinic anhydride having an acidnumber of 97 and an equivalent weight of 577 is prepared by the reactionof a chlorinated polyisobutene (having an average molecular weight of1000 and a chlorine content of 4.5%) and maleic anhydride. To a mix-vture of 88 parts (1.1 equivalents or 0.55 mole) of a 72% aqueoussolution of hexamethylene diamine and 415 parts of mineral oil, there isadded 577 parts (1 equivalent or 0.5 mole) of thepolyisobutene-substituted succinic anhydride at 6080 C. within a periodof 1 hour. The mixture is heated at 150155 C. for 5 hours while nitrogenis bubbled through the mixture. It is then heated to 180 C./20 mm. andfiltered. The filtrate is an oil solution containing 40% of thepolyisobutene-substituted succinirnide of hexamethylene diamine. Thesolution is found to have a nitrogen content of 1.4% (the theoreticalnitrogen content of the imide is 1.3%). v

The principal utility of the polyisobutene-substituted succinimides ofthis invention is as detergent additives in lubricating oils. They alsoare useful in other compositions, especially hydrocarbon compositionssuch as gasolines, burner fuel oils, cutting oils, transformer oils,hydraulic fluids, etc. The concentration of the succinimides asadditives in such compositions may range from about 0.1% to about byweight. For example, lubricating compositions for use. in gasolineinternal combustion engines may contain from about 0.5% to about 5% ofthe additive, lubricating compositions for use in gears and dieselengines may contain as much as 10% or even more of the additive, andgasolines and burner fuel oils may contain as little as 0.001% or evenless of the additive.

The lubricating oils in which the additive of this invention are usefulmay be of synthetic, animal, vegetable, or

mineral origin. Ordinarily mineral lubricating oils are preferred byreason of their availability, general excellence, and low cost. Forcertain applications oils belonging to one of the other three groups maybe preferred. For instance, synthetic polyester oils such as didodecyladipate and di-Z-ethylhexyl sebacate are often preferred as jet enginelubricants. Normally the oils preferred will be fluid oils ranging inviscosity from about 40 Saybolt Universal seconds at 100 F. to about 200Saybolt Universal seconds at 210 ,F.

To prepare the final oil compositions the additive'of this invention maybe added to the oil at the appropriate concentration. Alternatively, aconcentrate of the additive may be prepared by dissolving the additivein a limited amount of the oil and the concentrate may then be dilutedwith-additional amounts of the oil to prepare the final oilcompositions.

The lubricating compositions in which the additives of this inventionare present may contain other additives such as supplemental ashlessdetergents, metal cont a'ining detergents, corrosion inhibitors, rustinhibitors, oxidation inhibitors, load-carrying additives, anti-foamadditives, pour point depressants, viscosity index improving agents,-additives to improve the frictional characteristics,

etc. The concentrations of these additives in the lubricatingcompositions may range from about 0.001% to by weight;

A specific example of a lubricating composition useful in the crankcaseof an automobile is a SAE mineral lubricating oil containing-1.5% (byweight) of the product of Example 1. (Ether examples of lubricatingcompo- 5 sitions include: SAE mineral lubricating oil containing 3% ofthe product of'Exarnple 1 and 1% of zinc dioctylphosphorodithioate; SAE20 mineral lubricating oil containing 0.5% of the product of Examplel,1% of barium didodecyl benzene sulfonate, and 2% of2,6-ditert-butyl-4-methylphenol; and SAE 30 mineral lubricating oilcontaining 3% of the product of Example 1, 1.5 of his (octylphenyl)sulfide,.and 1% of-dibutyl tetrasultide.

The effectiveness of the succinimides of this invention as additives inlubricating compositions to prevent the formation of harmful deposits isshown by an oxidationdispersancy test which is useful as a screeningtestfor determining the efiectiveness of the additive under light dutyservice conditions. in this test a' 350cc. sample of a lubricating oilcontainingtheadditive .is placed in a A 1%x5 /s" SAE 1020 The samplethen is heated at 300 F. for 48 hours while air is bubbled through theoil at the rate of 10 liters per hour. The oxidized sample is cooled toF, homogenized with 0.5% by volume of water, allowed to stand at roomtemperature for 24 hours and then filtered through two layers of No. 1Whatinan filter paper at 20 mm. mercury pressure. The weight of theprecipitate, washed with naphtha and dried, is taken as a measure of theeffectiveness of the additive, i.e., the greater the weight of theprecipitate the less effective the dispersant additive. By this test aNidContinent, conventionally refined petroleum oil having a viscosity of200 SayboltUniversal seconds at 100 F. andcontaining 0.001% by weight ofiron naphthenatc (to promote oxidation) isfound to give 900-1000milligrams of sludge per 100 cc. of the oil sample whereas the sameoilcontaining additionally 1.5% by weight of the polyisobutenesubstituted succinimidc of hexamethylene diarnine gives only milligramsof sludge per 100 2" x15" borosilicate tube. steel panel is immersed in(113' oil.

cc. of the oil sample.

W at is claimed is: p 1. A succinimide having the structural formulawherein R is a polyisobutene radical having from about 0 to about 200carbon atoms.

2. The succinimide of claim 1 wherein R is a polyiso- 55 butene radicalhaving about 75 carbon atoms.

References Cited by the'Exarniner UNITED STATES PATENTS l-llCHOLAS S.RIZZO, Primary Examiner.

: DANIEL E. WYMAN, WALTER A. MODANCE,

' Examiners.

1. A SUCCINIMIDE HAVING THE STRUCTURAL FORMULA